Field of the Invention
The present invention relates to an image forming apparatus, an image forming system, and an image formation control method. In particular, the present invention relates to a technique to handle an adjustment chart appropriately.
Description of Related Art
In an image forming apparatus which forms images on both sides of a sheet, depending on the intended use purpose of a resultant printed sheet of image formation, it is important that the respective positions of images on the both sides coincide with each other. For this reason, according an existing technique, a chart in which an exclusive pattern is formed on its both sides is output by an image forming apparatus. Then, an operator measures the respective positions of the charts on both sides, and inputs the measurement results from an operating section. Subsequently, the operator performs position adjustment for the both sides on the inside of the image forming apparatus.
However, in such an adjustment technique, measurement varies depending on operators, and measurement results are input erroneously. Accordingly, the influence of errors caused by operators becomes greater. Consequently, it has been difficult to perform position adjustment for both sides correctly.
On the other hand, according to another existing technique, in order to eliminate such an error caused by operators, an exclusive chart is read with a scanner, the read results are analyzed on the inside of an image forming apparatus, and then, position adjustment is performed for both sides. In this case, in order to eliminate the influence of reading errors of the scanner, it is necessary to read one end and the other end, in the long side direction, of the front surface of an exclusive chart and one end and the other end, in the long side direction, of the back surface of the exclusive chart at the same position of the scanner.
With regard to execution of position adjustment for both sides of a sheet by using an exclusive chart, in Japanese Unexamined Patent Publication No. 2002-23991 (Document 1), several propositions have been made.